The First World War was an unprecedented catastrophe that killed millions and set the continent of Europe on the path to further calamity two decades later. But it didn’t come out of nowhere. With the centennial of the outbreak of hostilities coming up in August, Erik Sass will be looking back at the lead-up to the war, when seemingly minor moments of friction accumulated until the situation was ready to explode. He'll be covering those events 100 years after they occurred. This is the 111th installment in the series.

April 9, 1914: Tampico Incident Brings U.S., Mexico to Brink of War

Anyone who expresses amazement that China and Japan might come to blows over a couple of tiny, barren rocks would do well to consider the Tampico Incident, when the United States and Mexico almost went to war over nothing. Well, almost nothing.

By April 1914, the Mexican Revolution had degenerated into a civil war between multiple factions including the beleaguered federal government under Victoriano Huerta, peasant revolutionaries rallying to Emiliano Zapata, and the “Constitutionalists” led by Venustiano Carranza. On the east coast of Mexico, Carranza’s forces were laying siege to the port city of Tampico, in Tamaulipas state, which was held by a smaller force of federal troops as well as some state troops. Meanwhile U.S. President Woodrow Wilson dispatched a small naval force under Rear Admiral Henry T. Mayo to protect American citizens and property, including investments in the local oil industry. Although the U.S. government refused to recognize Huerta’s regime, the American forces stayed out of the fight and the situation remained calm—at first.

On April 9, 1914, the commander of the U.S.S. Dolphin sent nine sailors ashore in a whaleboat to pick up some cans of fuel oil from a warehouse in Tampico, as previously agreed with the Mexican federal commander. However, as the sailors were transferring the cans to the whaleboat, they were stopped by Tamaulipas state troops, who hadn’t been informed of the plan.

After a brief but tense armed standoff (naturally no one on either side spoke the other side’s language) the Mexican state troops arrested the U.S. sailors, including two who were ordered out of the whaleboat at gunpoint—technically, a violation of U.S. sovereignty, as naval vessels are considered national soil. The sailors were then paraded through the streets of Tampico to the headquarters of the federal commander, who recognized the mistake and ordered them released. Following a bit more confusion, and an official complaint by Mayo and the U.S. consul, the sailors were returned to the Dolphin with no harm done.

Or so it seemed. While the Mexican federal commander apologized for the mistake, he balked at Admiral Mayo’s demand that he raise the U.S. flag over Mexican soil for a 21-gun salute—an obvious affront to Mexican national pride—as restitution for the earlier alleged violation of U.S. sovereignty. Now, the seemingly minor incident started to spiral rapidly—and absurdly—out of control.

Back in Washington, D.C., President Wilson, who openly despised Huerta, claimed that the whole incident was part of a “pattern” of hostile and disrespectful behavior by Mexico, and repeated the demand for a salute to the U.S. flag. Huerta, who openly reciprocated Wilson’s feelings, of course refused, and Wilson in turn rejected Huerta’s counter-offer of a simultaneous salute by U.S. and Mexican troops.

Incredibly, the situation was about to get even worse, as Wilson ordered ships from the U.S. Atlantic and Pacific fleets to Mexican waters and asked Congress for permission to occupy a number of Mexico’s east coast ports, including the key city of Veracruz (but oddly enough not Tampico). On April 21, 1914, U.S. Marines landed in Veracruz and cleared Mexican forces from the city over the next few days, at a cost of 19 American and 150 Mexican dead. Meanwhile, on the west coast, U.S. ships made a show of force in the harbor of Mazatlan.

U.S. forces remained in Veracruz until November 1914, when the dispute was finally settled at the Niagara Falls Conference, but the Tampico Incident foreshadowed further American intervention in Mexico during the Punitive Expedition that attempted, unsuccessfully, to capture Pancho Villa from March 1916 to February 1917. Around this time, the continuing tensions seemed to offer Germany an opportunity to distract the U.S. and prevent it from joining the First World War by embroiling it in a war with Mexico instead, leading to the infamous Zimmerman Telegram—a ham-handed covert initiative that ended up backfiring disastrously.